If you’ve been following my blog posts thus far, you may recall that our body has clocks. We have a clock in the retina of the eye (the eye clock) that communicates directly with the central clock in the brain, and then we have all the peripheral clocks that control day/night activities like digestion, activity/exercise, immune function, endocrine function, growth & metabolism, sleep, etc. The eye clock wakes up the brain by absorbing light through photoreceptors in the retina, and passing it through the optic nerve reaching the Suprachiasmatic Nucelus (SCN) in the hypothalamus of the brain. From here, the SCN (central clock) communicates with all the peripheral clocks in a 24 hour cycle known as the circadian rhythm that is completely yoked to the natural light cycle of the sun.
Before I go any further, I want you to ask yourself an important question. Based on the above paragraph, what is more important: the food you eat, and the exercise you perform, or the light you are exposed to? It seems today everyone, including medical professionals are completely ignorant to the impact of light on our health. We have forgotten that all peripheral clocks (i.e. the ones that control feeding & activity) are controlled by the central clock (the SCN), and the central clock is entrained by light. So if we are missing the proper light signal, our peripheral clocks will not run properly and we can't achieve optimal health no matter what we do.
Here’s another question to ponder: why did mother nature put a clock in our eye that activates all other clocks in the body? Because our eye is above all other organs in the body, and is ALWAYS within the closest proximity to the sun. Why does this matter? Because the eye is the FIRST pathway for light to travel. This means that our eye clock is meant to run faster than any other clock. This is so crucial to our health because the eye clock is our timekeeper, and constantly needs to sense our environment in order to pass along the information to our peripheral clocks so we can thrive in said environment. So what happens when we consistently alter our environment by avoiding the sun during the day, and using artificial lighting at night? Our eye clock is unable to distinguish between night and day, and this sends mixed signals to peripheral clocks thus creating a mismatch. For example, if you spend most of the day indoors with a lack of natural sunlight, and use artificial lighting, you will not get a strong enough stimulus to run your eye clock at the right speed to coordinate daytime activities. That is because natural sunlight provides an illuminance of over 100,000 lux. Typical office lighting provides about 500 lux. Even the cloudiest day provides a higher illuminance than that (i.e. 1,000 lux). On the contrary, when we use artificial lighting at night, we are overstimulating the eye clock creating another mismatch and confusing the body by turning night into day. That is because moonlight (from a full moon) is less than 1 lux, while artificial light as mentioned is somewhere around 500 lux. When you extend your day beyond the natural light cycle, overtime, you are burning out your peripheral systems, and phase shifting your circadian rhythms, and lose the ability to sense the environment. When you cannot adapt to an environment for any reason, you will not do well period. This is how disease begins because you essentially disrupt the regenerative pathways that are activated in us that require darkness and sleep.
Let’s examine how our bodies are designed to function in harmony with the sunlight cycle. At sunrise, light hits the retina of our eye, and travels to the brain via the retinohypothalamatic tract (RTH). Within this tract lies retinal ganglion cells that contain a photoreceptor known as melanopsin. Melanopsin is most sensitive to the wavelength of light in the 460-480 nm range which is blue light. When this light reaches the SCN, there are two signals sent: 1) to shut off the pineal gland and 2) to activate the pituitary gland. The pituitary gland then releases its hormones that control endocrine function to help prepare us for the day, and start up the peripheral daytime clocks. An important question is why would melanopsin respond to blue light? Well it just so happens that the short blue light wavelength scatters more than all other wavelengths of light. Therefore, when the sun is up, blue light is scattered across the atmosphere making the sky appear blue. Because we cannot perceive a full spectrum of light in the sky (unless there is a rainbow), the blue sky is an indicator to our eye clock that it is daytime.
A few hours later, UV light appears from the sun. We have another photoreceptor known as neuropsin found in the cornea, and it has a peak response to 380 nm light which just so happens to be in the UV range. Neuropsin is used for the creation of biogenic amines which are synthesized from the aromatic amino acids tryptophan and tyrosine which all absorb UV light. Trytophan is the precursor to serotonin and melatonin and tyrosine is the precursor to dopamine. Additionally, when UVB light appears closer to "solar noon" in spring and summer, our skin absorbs these frequencies to make Vitamin D from cholesterol. Vitamin D plays a critical role in immunity, protecting us from infections, managing allergies and other immune reactions (i.e. autoimmune diseases) as well as cancer.
It should now be clear to you just how critical UV light is to our health. Without it, we cannot regenerate the melatonin or dopamine cycle let alone optimize immunity via Vitamin D. That’s why wearing sunglasses and sunscreen makes no freaking sense to me whatsoever. The UV light scare tactic is used by optometry and dermatology industries to make profits. Check out this study: https://www.ncbi.nlm.nih.gov/pubmed/22213311. It appears that UVB exposure protects against nearly all forms of cancer. People tend to overlook the regenerative properties of UV light, and it is that irresponsibility of avoiding UV exposure to the eye and skin that is creating an eruption of neolithic disease.
As the day goes on, and the sun begins to set, we lose the short wavelengths of light including UV and blue light, and see a shift to orange and red light (as seen in a sunset). These are longer wavelengths of light that emit less energetic photons, thus it only makes sense that we feel a sense of relaxation as the sun sets, because our energy levels are steadily falling. Serotonin is now being released in the brain. Because it comes from the aromatic amino acid tryptophan which is regenerated during the day under UV light, the more sunlight you were exposed to during the day, the higher the serotonin release will be (hint: there is your natural cure for depression). When darkness sets in, serotonin begins conversion into melatonin released by the pineal gland, which peaks after 3-4 hours of complete darkness. Melatonin is the most potent endogenous anti-oxidant that we have, and it protects our body from oxidative stress during sleep. While melatonin is slowly rising, leptin is now being released from our fat stores (as long as we don't eat late at night). Once melatonin peaks within a couple hours of falling asleep, our body temperature is lowered, and leptin enters the brain which upregulates the thyroid to uncouple proteins in the mitochondria to burn off excess fat as heat. Additionally, our body releases a massive surge of growth hormone at this time which facilitates a regenerative process known as autophagy. Autophagy allows us to recycle damaged proteins, so we don't have to replace them with stem cells.
Once these important regenerative processes are completed, we start to see a sharp rise in cortisol in the early hours of the morning to prepare us for the most stressful moment in a 24 hour period: awakening. Once the sun rises, we are back to the beginning of the cycle: pineal gland shut off by blue light, halting melatonin release, and the pituitary is activated to release cortisol, testosterone, progesterone and estrogen which peak around midmorning.
So a few considerations here. A lack of bright light in the early morning causes a delay in turning off the pineal gland and melatonin. This results in waking up groggy and needing a coffee as a stimulus to get your dopamine boost and cortisol release. Additionally, when you spend most of the day indoors, or use sunglasses outside, you are blocking the UV light in your eye, thus disrupting your ability to make the biogenic amines (dopamine, serotonin, and melatonin) which means you will feel less relaxed at night, and eventually depressed from low serotonin, your sleep will suffer due to a lack of melatonin, and you will be groggy and unmotivated in the morning from low dopamine. Additionally, when you wear sunscreen and cover your skin from the sun in summer, you will lack Vitamin D, which opens the door to cold/flu, allergies, intolerances, autoimmune diseases, and cancer. On the contrary, when you use artificial lighting at night (especially from LED technology, i.e. LED bulbs, laptops, phones, tablets, TV or fluorescent lights) you will activate activate melanopsin, and suppress melatonin so the regenerative processes that occur in the "window of darkness" will be disrupted. If this becomes chronic, our body will degenerate and we will age quickly, and succumb to preventable diseases.
Once these important regenerative processes are completed, we start to see a sharp rise in cortisol in the early hours of the morning to prepare us for the most stressful moment in a 24 hour period: awakening. Once the sun rises, we are back to the beginning of the cycle: pineal gland shut off by blue light, halting melatonin release, and the pituitary is activated to release cortisol, testosterone, progesterone and estrogen which peak around midmorning.
So a few considerations here. A lack of bright light in the early morning causes a delay in turning off the pineal gland and melatonin. This results in waking up groggy and needing a coffee as a stimulus to get your dopamine boost and cortisol release. Additionally, when you spend most of the day indoors, or use sunglasses outside, you are blocking the UV light in your eye, thus disrupting your ability to make the biogenic amines (dopamine, serotonin, and melatonin) which means you will feel less relaxed at night, and eventually depressed from low serotonin, your sleep will suffer due to a lack of melatonin, and you will be groggy and unmotivated in the morning from low dopamine. Additionally, when you wear sunscreen and cover your skin from the sun in summer, you will lack Vitamin D, which opens the door to cold/flu, allergies, intolerances, autoimmune diseases, and cancer. On the contrary, when you use artificial lighting at night (especially from LED technology, i.e. LED bulbs, laptops, phones, tablets, TV or fluorescent lights) you will activate activate melanopsin, and suppress melatonin so the regenerative processes that occur in the "window of darkness" will be disrupted. If this becomes chronic, our body will degenerate and we will age quickly, and succumb to preventable diseases.
Do you still believe you can fix your health by ignoring the effects of light on our circadian biology? Do you still think diet, supplementation, exercise and meditation will dig you out of the hole you're in? It all starts with light folks...
No comments:
Post a Comment